In general, the present invention relates to cooling systems for electronic circuitry, and more particularly, to a new compact ventilation unit for operative arrangement within a computerized apparatus having at least two powered air movers, located in stacked relationship to one another, each air mover having its own exhaust port.
It is well known that electronic equipment, and specifically computerized devices, generate thermal energy when powered-up and operating. To prevent component failure and early degradation due to overheating, heat must be vented from within computerized devices. As the overall size of computerized devices continues to decrease with new models, the speed and the size of memory and fixed storage of these devices has dramatically increased. These newer models often have many more electronic components and printed circuit boards (upon which components are mounted), compacted into a smaller chassis. Regulating the temperature of many electronic components within a smaller chassis has become a challenge. There is simply too little space available in newer model computerized devices to accommodate known ventilation systems. Particularly, a smaller chassis has less available "real estate" on its external back panel where connectors, peripheral connection ports, ventilation exhaust ports, and fasteners compete for space.
Currently available ventilation systems for computers have side-by-side fans mounted so that their axes of rotation extend perpendicular to the chassis outer back wall drawing common air from the inside of the computer through the fan blades and directly out of the chassis. See, for example, the ventilation systems described in U.S. Pat. Nos. 5,339,214; 4,751,872; 4,767,262; 5,193,050; 5,285,347; 5,490,723; 4,899,254; 5,505,533; and 5,247,427. Since the fans used in such known ventilation systems must be sized to fit within available back panel real estate limitations, the volume of warm air removed by known ventilation systems is necessarily limited. Increasing the diameter of the fans in known systems greatly increases the ventilation system's overall size, requiring an equally large increase in the back panel space needed for installation.
The assignee hereof filed a patent application (Ser. No. 08/770,890) on behalf of the Applicants of the instant patent application, on Dec. 20, 1996 entitled Compact Ventilation Unit for Electronic Apparatus. The invention disclosed in both this patent application and the earlier-filed pending patent application (Ser. No. 08/770,890) were invented by Applicants while employed by the assignee.
Known ventilation systems, as designed, do not adequately allow for increased air removal without a corresponding substantial increase in the chassis space required for installing the system. For example, to increase the volume of warm air removed by the side-by-side ventilation system in U.S. Pat. No. 4,767,262, more side-by-side fans had to be added with their axes of rotation also extending perpendicular to the chassis outer back wall. In another example, to increase the cooling within desktop personal computer chassis 200 of U.S. Pat. No. 5,572,403, inventor Mills added a second cooling fan downstream of the first fan so that both fans are coaxially aligned within a common plenum 430. In most computerized devices, chassis real estate is not available to accommodate more powerful ventilation systems having large external exhaust port space requirements. Without reasonable solutions at hand for adequately ventilating the interior space of a complex electronic instrument, an electronic designer can be severely limited in component and printed circuit board design alternatives.
The new compact ventilation unit, described herein, is designed for operation within a wide range of electronic apparatuses that require removal of unwanted thermal energy generated by electronic components during use. This innovative unit has the capacity to remove a greater amount of thermal energy to maintain desired component operating temperatures within a computerized device, without requiring a substantial increase in the size of its side containing airflow exhaust ports. Less exterior computer housing real estate is needed to install the present invention than for known cooling systems. Furthermore, this new unit can be installed and removed with relative ease and it can reach further into the interior of an electronic device to expel heat generated within, out an exterior (usually, located on the back) housing panel. The new unit incorporates a redundant powered air mover to lower the chance of component overheating and can accommodate suitable couplings for hot plugging into an electronic apparatus as necessary.
Unlike the ventilation systems currently available comprised of propeller fans having axes of rotation extending perpendicular to the chassis back wall, the new unit and new method were developed to utilize chassis wall space more efficiently while at the same time provide sufficient ventilation. As will be explained, a third and fourth fan, and so on, can be added to the new unit described herein, in the spirit of this design goal.